Blinded by the Light: Artificial Light Lowers Mate Attraction Success in Female Glow-Worms (Lampyris noctiluca L.)

Nocturnal light pollution from anthropogenic origin is increasing worldwide and is recognised as a major threat for nocturnal biodiversity. We studied the impact of artificial light on the mate attraction success of female common glow-worms (Lampyris noctiluca L.) by daily monitoring their glowing status in the field, acting as a proxy for mating status throughout the mating season. We found that females in dark surroundings typically stopped glowing after one night, indicating that they had mated, while females in illuminated areas glowed for significantly more nights, in some cases up to 15 nights. Our study confirms previous findings and hypotheses that females exposed to artificial light suffer from a reduced mate attraction success with a negative impact on populations.

Analysis of Honeybee Drone Activity during the Mating Season in Northwestern Argentina

Males in Hymenopteran societies are understudied in many aspects and it is assumed that they only have a reproductive function. We studied the time budget of male honey bees, drones, using multiple methods. Changes in the activities of animals provide important information on biological clocks and their health. Yet, in nature, these changes are subtle and often unobservable without the development and use of modern technology. During the spring and summer mating season, drones emerge from the hive, perform orientation flights, and search for drone congregation areas for mating. This search may lead drones to return to their colony, drift to other colonies (vectoring diseases and parasites), or simply get lost to predation. In a low percentage of cases, the search is successful, and drones mate and die. Our objective was to describe the activity of Apis mellifera drones during the mating season in Northwestern Argentina using three methods: direct observation, video recording, and radio frequency identification (RFID). The use of RFID tagging allows the tracking of a bee for 24 h but does not reveal the detailed activity of drones. We quantified the average number of drones’ departure and arrival flights and the time outside the hive. All three methods confirmed that drones were mostly active in the afternoon. We found no differences in results between those obtained by direct observation and by video recording. RFID technology enabled us to discover previously unknown drone behavior such as activity at dawn and during the morning. We also discovered that drones may stay inside the hive for many days, even after initiation of search flights (up to four days). Likewise, we observed drones to leave the hive for several days to return later (up to three days). The three methods were complementary and should be considered for the study of bee drone activity, which may be associated with the diverse factors influencing hive health.

Beautiful on the Inside

Marine iguanas stand in stark contrast to the Galápagos rails. They vary enormously in space by size and color, supporting classification into 11 subspecies (whereas rails are monotypic). And they vary in time, especially males, which change to bright colors in the mating season—some to the point of being bright red and green “Christmas iguanas.” They vary over time in an additional special way: iguanas shrink up to 20% (or 2.7 inches) during the food scarcity of El Niño events. They have evolved the capacity to shut down their normal stress response when the ocean gets warm, thus becoming quiescent and riding out the storm. The larger the iguanas, the more they shrink and the longer they survive. Furthermore, nearly all marine iguana subspecies have increased in size since 1905, while, at the same time, climate change has made El Niño events stronger and longer. Could climate change be driving the evolution of larger marine iguanas? Will iguanas be able to keep up as El Niño worsens?

Cooperative partner choice in multi-level male dolphin alliances

Investigations into cooperative partner choice should consider both potential and realised partners, allowing for the comparison of traits across all those available. Male bottlenose dolphins form persisting multi-level alliances. Second-order alliances of 4–14 males are the core social unit, within which 2–3 males form first-order alliances to sequester females during consortships. We compared social bond strength, relatedness and age similarity of potential and realised partners of individual males in two age periods: (i) adolescence, when second-order alliances are formed from all available associates, and (ii) adulthood, when first-order allies are selected from within second-order alliances. Social bond strength during adolescence predicted second-order alliance membership in adulthood. Moreover, males preferred same-aged or older males as second-order allies. Within second-order alliances, non-mating season social bond strength predicted first-order partner preferences during mating season consortships. Relatedness did not influence partner choice on either alliance level. There is thus a striking resemblance between male dolphins, chimpanzees and humans, where closely bonded non-relatives engage in higher-level, polyadic cooperative acts. To that end, our study extends the scope of taxa in which social bonds rather than kinship explain cooperation, providing the first evidence that such traits might have evolved independently in marine and terrestrial realms.

Sexual Interference Behaviors in Male Adult and Subadult Tibetan Macaques (Macaca thibetana)

Male nonhuman primate sexual interference, which includes copulation interruption and copulation harassment, has been related to reproductive success, but its significance has been challenging to test. Copulation interruption results in the termination of a copulation before ejaculation, whereas copulation harassment does not. We conducted this study using the all-occurrence behavior sampling method on sexual interference behaviors of seven adult and four subadult male Tibetan macaques (Macaca thibetana) in mating and non-mating seasons at Mt. Huangshan, China, from August 2016 to May 2017. Our results showed that males’ individual proportion of copulation interruption and harassment was higher during the mating season than during the non-mating season. In addition, dominant males more often performed interruption, whereas subordinate males more often performed harassment. We found no difference in the individual proportion of copulation interruption or harassment between adult and subadult males. Adult and subadult males both directed copulation interruption and harassment more often toward the mating male than toward the mating female. Lastly, the post-ejaculation phase of copulation was shorter when copulation harassment occurred than when it did not. Our results suggest that sexual interference may be an important mating tactic that adult and subadult males use in male–male sexual competition.

Social behavior of musk deer during the mating season potentially influences the diversity of their gut microbiome

An increasing body of research has revealed that social behavior shapes the animal gut microbiome community and leads to the similarity among the same social group. However, some additional factors (e.g., diet and habitat within each social group) may also contribute to this similarity within the social group and dissimilarity between social groups. Here, we investigated the potential correlation between social behavior and the gut microbiome community in 179 musk deer from four breeding regions in the Maerkang Captive Center, Sichuan. The dominant gut microbiome phyla in the musk deer in this study were Firmicutes, Bacteroidetes, and Proteobacteria. We found significant effects on the alpha and beta diversity of the gut microbiome due to the breeding regions. The similarity within breeding regions was higher than that between the breeding regions. Due to their solitary lifestyle, captive musk deer are raised in single cages with no direct social contact most of the time. Deer in all of the breeding regions have the same diet and similar living conditions. However, during each mating season from November to January, in each region, one adult male and about six adult females will be put together into a large cage. Social behavior happens during cohabitation, including mating behavior, grooming within the same sex or between different sexes, and other social contact. Therefore, we speculated that high similarity within the breeding region might be associated with the social behavior during the mating season. This was a simple and straightforward example of the relationship between animal social behavior and the gut microbiome.

Antiparasitic Effects of Plant Species from the Diet of Great Bustards

Background: Diets combine food types according to some trade-offs, as for example maximising nutrients and minimising toxins. But some diets include elements because of their activity against the host parasites and other pathogens. This so-called medicinal role of food is under-reported in the literature, either because toxic elements in diets of livestock and wildlife are infrequent, or because their activity against parasites and pathogens has not been fully documented. We contribute to fill this knowledge gap by testing the activity of extracts and essential oils from Papaver rhoeas and Echium plantagineum against a selection of laboratory pathogens. These plants are strongly selected by great bustards Otis tarda during the mating season. Results: During this season we found a significantly higher frequency of P. rhoeas in male than in female faeces. The activity of different extracts of these plants against some laboratory models including a flagellated protozoan (Trichomonas gallinae), a nematode (Meloidogyne javanica) and a fungus (Aspergillus niger) was evaluated. We found activity against nematodes and trichomonads in non-polar and polar extracts of the aerial parts of P. rhoeas, especially the extracts of flowers and capsules, and E. plantagineum, especially the extracts of leaves and flowers.Conclusions: Both plants showed anti-parasitic activity, a result compatible with the hypothesis that great bustards eat plants for non-nutritional purposes, likely to assist them in coping with parasites and other pathogens, and P. rhoeas could be especially helpful for males during the mating season, when their immune system is weakened by the investment in secondary sexual characters and sexual display. The self-medication properties of plants and animals included in diets should be considered in studies of foraging behaviour, habitat selection, and even conservation biology of wildlife.

The Greater Proportion of Born-Light Progeny from Sows Mated in Summer Contributes to Increased Carcass Fatness Observed in Spring

The backfat of pig carcasses is greater in spring than summer in Australia. The unexplained seasonal variation in carcass backfat creates complications for pig producers in supplying consistent lean carcasses. As a novel explanation, we hypothesised that the increased carcass fatness in spring was due to a greater percentage of born-light progeny from sows that were mated in summer and experienced hot conditions during early gestation. The first part of our experiment compared the birth weight of piglets born to the sows mated in summer (February, the Southern Hemisphere) with those born to sows mated in autumn (May; the Southern Hemisphere), and the second part of the experiment compared the growth performance and carcass fatness of the progeny that were stratified as born-light (0.7–1.1 kg) and born-normal (1.3–1.7 kg) from the sows mated in these two seasons. The results showed that the sows mated in summer experienced hotter conditions during early gestation as evidenced by an increased respiration rate and rectal temperature, compared with those mated in autumn. The sows mated in summer had a greater proportion of piglets that were born ≤1.1 kg (24.2% vs. 15.8%, p < 0.001), lower average piglet birth weight (1.39 kg vs. 1.52 kg, p < 0.001), lower total litter weights (18.9 kg vs. 19.5 kg, p = 0.044) and lower average placental weight (0.26 vs. 0.31 kg, p = 0.011) than those mated in autumn, although litter sizes were similar. Feed intake and growth rate of progeny from 14 weeks of age to slaughter (101 kg live weight) were greater for the born-normal than born-light pigs within the progeny from sows mated in autumn, but there was no difference between the born-light and normal progeny from sows mated in summer, as evidenced by the interaction between piglet birth weight and sow mating season (Both p < 0.05). Only the born-light piglets from the sows mated in summer had a greater backfat thickness and loin fat% than the progeny from the sows mated in autumn, as evidenced by a trend of interaction between piglet birth weight and sow mating season (Both p < 0.10). In conclusion, the increased proportion of born-light piglets (0.7–1.1 kg range) from the sows mated in summer contributed to the increased carcass fatness observed in spring.

The size of signal detection and emission organs in a synchronous firefly: sexual dimorphism, allometry and assortative mating

The size of the organs responsible for emitting and detecting sexual communication signals is a likely target for selection. Communication via bioluminescent signals in synchronous fireflies is a promising model to test hypotheses regarding differences between males and females in the effect of the size of signal emission and detection organs on fitness components. Synchronous firefly species congregate in large numbers during the mating season, displaying bioluminescent signals aimed at potential mates during relatively short nightly periods. Operational sex ratios are male-biased and, thus, the so-called typical sex roles (indiscriminate males and choosy females) are expected to evolve. We studied the synchronous firefly Photinus palaciosi, a species that during the mating season congregates in forests of central Mexico offering a magnificent natural show that attracts numerous tourists. P. palaciosi females have reduced wings (brachyptery) and cannot fly. Our field study tested the hypothesis that the male-biased operational sex ratio and the short daily mating period result in strong male-male competition that selects for males with larger lanterns and larger eyes, and against male mate choice, whereas female-female mate competition is absent and, thus, no selection on lantern or eye size is expected. Even though lantern, eye or body size do not predict the probability of being found in copula for either sex, sexual dimorphism in these features, along with allometric slopes of lantern size and assortative mating in terms of relative lantern size, support not only the hypothesis of intense sexual selection among males, but the possibility of subtle mechanisms of sexual selection among females. Trade-offs between investment in signaling (lanterns) versus detection (eyes) structures, or with pressures different from sexual selection such as those imposed by predators, are also likely to be important in shaping the evolution of sexual signaling in these fireflies.

“Hey, It’s Me, It’s Me!” Courtship and Confusion in the Male Reproductive Strategy

This chapter addresses why male anacondas are so much smaller than females. There are a number of advantages for animals to be small. Small animals have lower metabolic costs since they need to maintain only a small body that requires less food. Animals that need less food have potentially higher survival than those that have a large body to maintain. This is particularly important in droughts or times of food shortages. A small body is also an asset because it lowers the cost of locomotion. Hauling around a large body incurs larger energetic expenditures than if the body is small. This is particularly important for males that move much more than females in the mating season to track receptive females for mating. Being small also offers other benefits, such as being inconspicuous, not being a very coveted meal, and hiding easily from potential predators. Of course, there are also some disadvantages of being small. Small animals cannot fight off predators as well as large ones and are limited by their gape to what kind of prey they can eat. Furthermore, larger males may produce more sperm, which would give them an advantage in siring more offspring, particularly in those cases where the female mates with several males.